1. Field of the Invention
The present invention relates to a socket for electrical parts for detachably accommodating and holding an electrical part such as a semiconductor device (called xe2x80x9cIC packagexe2x80x9d hereinlater), and more particularly, relates to a socket for electrical parts capable of solving defect or inconvenience caused at a time of narrowing a pitch of terminals of the electrical part.
2. Related Art of the Invention
In prior art, there is known, as such xe2x80x9csocket for an electrical partxe2x80x9d, an IC socket to which an IC package, as xe2x80x9celectrical partxe2x80x9d, is mounted to thereby establish an electrical connection between the IC package and a printed circuit board of, for example, a tester.
In such IC package, a number of solder balls as terminals are arranged to the lower surface of the IC package so as to extend or project downward in a using state of the IC socket so as to provide a lattice arrangement having vertical and horizontal rows.
On the other hand, the IC socket is provided with a socket body to which the IC package is mounted and accommodated and a number of contact pins are arranged so as to be contacted to terminals (i.e., solder balls) of the IC package. The socket body is also provided with a movable member, to be vertically movable, for elastically deforming the contact pins and thereby contacting or separating the contact pins to or from the terminals of the IC package. The socket body is further provided with an operation member for vertically moving the movable member through a lever member.
These contact pins are arranged adjacently and each of them has a pair of elastic pieces which contact both side portions of the solder ball of the IC package. These elastic pieces are elastically movable and opened in their interval according to the vertical motion of the movable member to thereby clamp or separate the solder ball.
In the prior art structure mentioned above, however, the elastic pieces of the contact pin is elastically deformed sideways, so that when it is required for the pitch of the solder ball to be made small, the arrangement pitch of the contact pins is also made small. This will adversely result in that the elastic piece easily contacts another elastic piece of an adjacent contact pin, thus providing a fear of occurrence of short circuit. It is therefore difficult to make small the pitch of the solder ball arrangement.
The present invention was conceived to solve the defect or disadvantage encountered in the prior art mentioned above and to provide a socket for an electrical part capable of solving inconvenience caused at a time of narrowing a pitch of terminals of the electrical part.
The above and other objects of the present invention can be achieved according to the present invention by providing a socket for an electrical part having a socket body in which a number of contact pins are arranged adjacently each other so as to contact terminals of an electrical part, a movable member is disposed so as to elastically deforming the contact pins, and an operation member is disposed to be vertically movable to thereby move the movable member, wherein each of the contact pins is provided with a pair of elastic pieces contacting the terminal of the electrical part, at least one of the elastic pieces is elastically deformed by the movement of the movable member so as to be contacted to or separated from the terminal of the electrical part, and when at least one of the elastic pieces is elastically deformed and separated from the terminal of the electrical part, the elastic piece of one of the contact pins and another elastic piece of an adjacent contact pin pass each other without contacting.
In a preferred embodiment, it is possible that the movable member is vertically moved in accordance with the vertical motion of the operation member so as to elastically deform both of the paired elastic pieces of the contact pin. The movable member may be horizontally slid in accordance with the vertical motion of the operation member so as to elastically deform both of the paired elastic pieces of the contact pin. Furthermore, the terminal of the electrical part is a solder ball having substantially spherical shape disposed to a surface of the IC package, and the paired elastic pieces of the contact pin are provided with contact portions, respectively, which are disposed on both side portions of the solder ball so as to interpose, therebetween, a center line of the solder ball along a displacement direction of the elastic pieces. In addition, a separation member is disposed to the socket body at a portion between one elastic piece of a contact pin and another elastic piece of the adjacent contact pin, and in such structure, the first mentioned elastic piece is elastically deformed and separated from the terminal of the electrical part, while passing each other.
In a modified aspect, there is provided a socket for an electrical part comprising:
a socket body;
a number of contact pins which contact terminals of an electricalpart for electrical connection;
a movable member disposed to the socket body for elastically deforming the contact pins;
an operation member disposed to the socket body to be vertically movable thereto for moving the movable member,
each of the contact pins comprising a pair of elastic pieces and contact portions formed to end portions of the elastic pieces, respectively, at least one of the elastic pieces being elastically deformed by the movement of the movable member so as to be contacted to or separated from the terminal of the electrical part, and when at least one of the elastic pieces is elastically deformed and separated from the terminal of the electrical part, the elastic pieces of the adjacent contact pins pass each other without contacting.
According to the present invention of the characters and structures mentioned above, when the elastic piece of one contact pin is elastically deformed and separated from the terminal of the electrical part, this elastic piece and one elastic piece of the adjacent contact pin pass each other without contacting, so that any defect such as short-circuit of the contact portions of the adjacent contact pins can be avoided. In addition, the pitch between the adjacent contact pins can be made small in comparison with the conventional structure and it is therefore possible to satisfy a requirement of making narrow the pitch. In addition, it is also possible to construct the contact portions of the contact pins so as to have the same displacement direction (open/close direction) with respect to the arrangement direction of the contact pins. Further, a mold for molding the socket body to which the contact pins are fitted can be easily manufactured.
Furthermore, when the contact portions of the elastic pieces of the contact pin are disposed on both the side surface portions of the solder ball and contact the side surfaces thereof, a wiping effect can be advantageously achieved.
Still furthermore, the location of the separation member between the elastic pieces of the adjacent contact pins can ensure the prevention of the contact portions of the contact pins from being contacted.
The nature and further characteristic features of the present invention will be made more clear from the following descriptions made with reference to the accompanying drawings.